Seen in its strictest sense, mastery learning is a recent phenomenon. Viewed in terms of its constituent elements, however, it has roots deep in the Western tradition of education. Elements of mastery learning theory can be found in the work of the Sophists; early Jesuit educators; John Amos Comenius, a Moravian pastor; John Locke; Johann Heinrich Pestalozzi; Johann Friedrich Herbart; and the American one-room school. The examples cited are indicative of the ways in which venerable educational traditions have broken ground for mastery learning. However, it is only in today's mastery learning theory that one finds all of the elements combined in this particular manner. (BW)